Siemens SIPROTEC 7SJ62 Manual page 106

Functions
2.3 Directional Overcurrent Protection 67, 67N
Table 2-7
Pickup
A
B
C
A, B with I >I
A B
A, B with I =I
A B
A, B with I <I
A B
B, C with I >I
B C
B, C with I =I
B C
B, C with I <I
B C
C, A with I >I
C A
C, A with I =I
C A
C, A with I <I
C A
A, B, C with I
A
A, B, C with I
B
A, B, C with I
C
Direction Determination of Directional Phase Elements
As already mentioned, the direction determination is performed by determining the phase angle between the
fault current and the reference voltage. In order to satisfy different network conditions and applications, the ref-
erence voltage can be rotated by an adjustable angle. In this way, the vector of the rotated reference voltage
can be closely adjusted to the vector of the fault current in order to provide the best possible result for the di-
rection determination. Figure 2-27 clearly shows the relationship for the directional phase element based on a
single-pole ground fault in Phase A. The fault current I
ence voltage, in this case V
ROTATION ANGLE, positively counter-clockwise. In this case, a rotation by +45°.
Figure 2-27
106
Voltage and Current Values for the Determination of Fault Direction in a Phase Element
I
A
I
B
I
C
I
A
I
A
I
B
I
B
I
B
I
C
I
C
I
A
I
A
>(I , I ) I
B C A
>(I , I )
I
A C B
>(I , I )
I
A B C
for the directional phase element A, is rotated by the setting value 1519
BC
Rotation of the reference voltage, directional phase element
Selected current
follows the fault voltage by fault angle ϕ
scA
C53000-G1140-C207-2, Release date 01.2008
Allocated voltage
V - V
B C
V - V
C A
V - V
A B
V - V
B C
V - V
B C
V - V
C A
V - V
C A
V - V
C A
V - V
A B
V - V
A B
V - V
B C
V - V
B C
V - V
B C
V - V
C A
V - V
A B
. The refer-
sc
SIPROTEC, 7SJ62/64, Manual